5-methyltetrahydrofolate

Levomefolic acid

Names
IUPAC name (2S)-2-[ [4-[(2-Amino-5-methyl-4-oxo-1,6,7,8-tetrahydropteridin-6-yl) methylamino]benzoyl]amino]pentanedioic acid
Other names (L-5-Me-THFA, L-5-Me-H4FA), anion: L-5-methyltetrahydrofolate (L-5-Me-THF, L-5-Me-H4F), L-methylfolate Metafolin
Identifiers
CAS Number	134-35-0 151533-22-1 (calcium salt)
3D model (Jmol)	Interactive image
ChemSpider	392351
KEGG	D09353
MeSH	5-methyltetrahydrofolate
PubChem	444412 15341110 (calcium salt)
UNII	8S95DH25XC Y
InChI InChI=1S/C20H25N7O6/c1-27-12(9-23-16-15(27)18(31)26-20(21)25-16)8-22-11-4-2-10(3-5-11)17(30)24-13(19(32)33)6-7-14(28)29/h2-5,12-13,22H,6-9H2,1H3,(H,24,30)(H,28,29)(H,32,33)(H4,21,23,25,26,31)/t12-,13-/m0/s1 Key: ZNOVTXRBGFNYRX-STQMWFEESA-N InChI=1/C20H25N7O6/c1-27-12(9-23-16-15(27)18(31)26-20(21)25-16)8-22-11-4-2-10(3-5-11)17(30)24-13(19(32)33)6-7-14(28)29/h2-5,12-13,22H,6-9H2,1H3,(H,24,30)(H,28,29)(H,32,33)(H4,21,23,25,26,31)/t12-,13-/m0/s1 Key: ZNOVTXRBGFNYRX-STQMWFEEBP
SMILES CN1c2c([nH]c(nc2=O)N)NC[C@@H]1CNc3ccc(cc3)C(=O)N[C@@H](CCC(=O)O)C(=O)O
Properties
Chemical formula	C20H25N7O6
Molar mass	459.46 g·mol−1
Pharmacology
ATC code	B03BB51 (WHO)
Pregnancy category	N
Routes of administration	oral, transdermal, subcutaneous
Legal status	US: OTC
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Levomefolic acid (INN) (also known as L-5-MTHF, L-methylfolate and L-5-methyltetrahydrofolate and (6S)-5-methyltetrahydrofolate, and (6S)-5-MTHF) is the primary biologically active form of folate used at the cellular level for DNA reproduction, the cysteine cycle and the regulation of homocysteine. It is also the form found in circulation and transported across membranes into tissues and across the blood-brain barrier. In the cell, L-methylfolate is used in the methylation of homocysteine to form methionine and tetrahydrofolate (THF). THF is the immediate acceptor of one carbon units for the synthesis of thymidine-DNA, purines (RNA and DNA) and methionine. The un-methylated form, folic acid (vitamin B₉), is a synthetic form of folate, and must undergo enzymatic reduction by methylenetetrahydrofolate reductase (MTHFR) to become biologically active.

It is synthesized in the absorptive cells of the small intestine from polyglutamylated dietary folate. It is a methylated derivative of tetrahydrofolate. Levomefolic acid is generated by MTHFR from 5,10-methylenetetrahydrofolate (MTHF) and used to recycle homocysteine back to methionine by methionine synthase (MS).

L-methylfolate is water-soluble and primarily excreted via the kidneys. In a study of 21 subjects with coronary artery disease, peak plasma levels were reached in one to three hours following oral or parenteral administration. Peak concentrations were found to be more than seven times higher than folic acid (129 ng/ml vs. 14.1 ng/ml).

Levomefolic acid (and folic acid in turn) has been proposed for treatment of cardiovascular disease and advanced cancers such as breast and colorectal cancers. It bypasses several metabolic steps in the body and better binds thymidylate synthase with FdUMP, a metabolite of the drug fluorouracil.